I get the same error at http://matrix.cpantesters.org/?dist=Math-MPC-1.33 right now.

The "fast" (log.txt) report (which is linked in the "Other Links" section of that empty report) at http://fast-matrix.cpantesters.org/?dist=Math-MPC-1.33 does have data.

The "fast2" (mdjson API) report at https://fast2-matrix.cpantesters.org/?dist=Math-MPC-1.33 does not have data.

Whenever I get an error or the data has not yet shown up at the main, I go try the log.txt(fast) version. (And for brand-new dists, I don't bother going to the default matrix.)

The fast2 is a newer link which I don't have enough experience with to really comment meaningfully on, but based on today's experiment, I'd say it's got the same data-limitation as the main matrix, even if it is, as it implies, a faster access to the data.